1. Field of the Invention
This invention relates to a golf club, and more particularly to a golf club which is improved to provide a longer travelling distance for a struck ball.
Specifically, the invention is applicable to any wood or iron clubs which are intended to provide a reasonable or considerable travelling distance of a hit ball. Thus, the invention is not applicable to putters which are designed to control the direction for a rolling ball and to improve the feeling of putting.
2. Description of the Prior Art
In golf, clubs are used as ball striking instruments. As is well known, the travelling distance of a struck ball is determined by the action of the golf club which governs the trajectory and initial speed of the ball. More specifically, the trajectory of the struck ball is influenced by the spin, trajectory angle and direction of the ball imparted by the club, while the initial ball speed is influenced by the club head speed and the coefficient of restitution.
Among these factors, the spin, trajectory angle and travelling direction of a struck ball are explained from the view point of dynamics with emphasis placed on the moment of inertia around the center of gravity of the club head. The speed of the club head is explained in relation to swing of the club with emphasis placed on the club shaft.
However, the coefficient of restitution involves the problem of the relationship between the golf ball and the golf club. Little has hitherto been described about the influences on the coefficient of restitution exerted when the club (head) strikes the ball.
Conventional golf clubs generally have heads made of persimmon wood (possibly with an ABS plastics insert of less than 8 mm in thickness), carbon-fiber-reinforced plastics (CFRP), aluminum, or stainless steel. A conventional view on the component materials is such that the harder the material, the greater the impact resilience to a golf ball (larger coefficient of restitution). Thus, the conventional view holds that harder materials will make the ball travel further or at a greater initial speed. Therefore, in the case of using carbon-fiber-reinforced plastics (CFRP) for example, a higher fiber content is believed preferable because of increased hardness and presumably increased coefficcient of restitution.